The present invention concerns a device, such as a trocar, which is intended to penetrate a human body wall in endoscopic surgical operations to establish a passageway for insertion of surgical instruments and extraction of specimens therethrough, and which comprises a through-passage sleeve having one proximal and one distal end.
Laparoscopic surgery, also known as keyhole surgery, has gained in importance in general surgery, gynecological surgery and urological surgery. The advantages compared with conventional surgery methods are considerable, both to the patient and to society. In the case of laparoscopic surgery operations small-dimension puncture orifices are made in the abdominal wall, through which trocars (tubular sleeves) of the kind mentioned in the introduction are inserted, and the laparoscope instrument as well as one or several operational instruments are introduced through the trocars. As a rule, the abdomen is inflated with gas, which increases the abdominal volume considerably, thereby providing an overall view and assessibility. The image of the surgical area is transmitted to a monitor and the diseased organ is isolated and separated from the surrounding tissue with the aid of the operational instruments. The surgical technique, the instruments, and other equipment for this purpose are already well known and highly developed. The specimen (the organ, the surgically removed tissue) must then be removed from the patient""s abdomen. When small size, the specimen may be pulled out directly through the trocar, but when it is larger, it is necessary to first fragmentise it into smaller pieces.
Many varieties of trocars are already known. One problem encountered in many of them is the difficulty in making them stay in place, a problem which may be solved by stitching projecting flanges on the trocar to the body wall. Another alternative is to expand the inserted distal end. This solution is known from e.g. U.S. Pat. No. 5,545,179, which document shows a trocar the distal end of which may be inflated like a balloon about the tube.
Under certain circumstances it is also useful if the trocar can be used to lift and abdominal wall (the wall of the abdominal cavity), above all in the case of so called gas-free laparoscopy. Special tools, known as laparolifters, have been developed for this purpose.
Another problem found in many trocars is the difficulty of imparting to the instruments that are introduced via the trocar as efficient movability and accessibility properties as possible. These objects are achieved in accordance with the prior-art technology by manufacturing the trocar from a soft and pliable material, thereby allowing the distal trocar end to shape itself in conformity with the instrument. Trocars of this kind are known from e.g. U.S. Pat. No. 5,634,911 and U.S. Pat. No. 5,391,156.
Furthermore, trocars are known wherein the tube diameters is changeable, thus able to be expanded or contracted. Trocars of this kind are known from U.S. Pat. No. 3,789,852, which describes a trocar the peripheral surface of which is arranged to overlap, and from U.S. Pat. No. 5,139,511.
One problem that prior-art trocars have so far failed to solve is the difficulty connected with the extraction of the specimen. The specimen or pieces of the specimen are often extracted directly through the trocar by means of a pair of tongs or the like. It is then desirable that it be possible to extract as large pieces as possible for speed efficiency and to reduce as far as possible the need to fragmentise the specimens. In addition, it is of course desirable that the through-passage orifices are as small as possible to minimise the surgical intervention and the patient""s discomfort. Consequently, it is desirable that the trocar is designed to be of assistance in guiding the specimen correctly as the latter is being introduced into the trocar tube, in order to prevent the specimen from sticking, from assuming an oblique position or the like. It is likewise desirable that the specimen be compressed as far as possible and be contracted so as to assume a spool-shape or similar configuration.
These and other problems are connected not only with laparoscopic surgery but under similar conditions with essentially all endoscopic surgery, including thorascopy surgery (laparoscopic surgery in the thorax cavity).
Consequently, one object of the present invention is to provide a device, which facilitates the extraction of specimens while at the same time it is comparatively firmly fixed to the body-cavity wall, thus at least partly solving the above described problems from which prior-art solutions suffer.
This object is achieved by means of a trocar of the kind defined in the appended claims.
The invention concerns a trocar intended to penetrate a body wall in endoscopic surgery to establish a passageway allowing insertion therethrough of surgical instruments, and comprising a tubular sleeve having one proximal and one distal end. The device in accordance with the invention is characterised in that the distal end is arranged to be contracted such that it assumes transverse dimensions not exceeding the surgical orifice to allow said end to be introduced into said orifice, and thereafter to expand when applied in position such that it assumes downwards gradually increasing dimensions transversely exceeding the dimensions of the device at the place of the surgical orifice, whereby a funnel-shaped distal end is formed.
Through the funnel-shaped end, the specimens to be extracted are guided straight into the tube while at the same time they are suitable orientated for extraction. The gradual contraction or size reduction of the distal trocar end in the direction towards the tube proper causes some squeezing-together also of the specimen, whereby the latter is compressed while at the same time no edges exist on which the specimen may be stuck while passing. In this manner extraction of specimens is highly facilitated and larger-size specimen pieces may be extracted and/or smaller trocars be used. In addition, the funnel-shaped configuration of the trocar end contributes to maintaining the device in position in the surgical orifice in the body wall.
In order to further strengthen the retaining capacity of the device, the latter could also be provided with locking means, such as a rocker element, which locks the trocar in the inserted operative position of the latter. A trocar of this kind represents a preferred embodiment of the device in accordance with the invention.
In accordance with another preferred embodiment of the invention at least the distal end of the trocar is made from a resilient material which in itself tends to assume the expanded position. In this manner, the device is easily inserted while in its contracted position, while the distal end, when released, assumes its expanded position. The latter position is then maintained automatically owing to the nature of the material. When the device is to be extracted, the extraction force will again compress the distal end, overriding the resiliency of the material.
Preferably, at least the narrowest part of the device is yieldable and thus has a variable size in the transverse direction. As a result, specimens of a slightly too large size may be pulled through the device, since in this case the tube will widen slightly. This arrangement causes the specimen to be compressed further while at the same time the sensitivity of the device to too large specimens diminishes.
Other advantageous pecularities of the invention will appear from the following description of embodiment of the invention.